This invention relates to refrigerant supply tank heating units for recharging refrigeration units, and in particular, to a portable on-site heating unit.
For various reasons, refrigeration units, such as air-conditioning units, refrigerators, etc., loose their refrigerant and must be recharged. Typically, the system being serviced is recharged simply by connecting it to a supply tank by means of a hose. Typically, the supply tank is a 30-50 lb. tank. The recharging process relies on the pressure differential between the refrigeration supply tank and the refrigeration system, and the refrigerant flows from the pressurized supply tank to the refrigeration unit which has a lower pressure than the supply tank. As long as the pressure in the supply tank is greater than the pressure in the refrigeration unit, refrigerant will flow unaided from the supply tank to the refrigeration unit.
As the target unit is filled, the supply tank empties, and the pressure differential between the two becomes smaller. As the pressure differential becomes smaller, the flow of refrigerant from the supply tank to the target unit slows, increasing the time it takes to fully fill the target unit. This problem is enhanced in cold weather, when the refrigerant supply tank is cold, and hence the refrigerant is at a lower pressure than on a warm day.
Service technicians have resorted to heating the supply tank to increase the pressure of the refrigerant in the supply tank. This overcomes the problem caused by the reduced pressure in the tank. However, I know of no unit which is not complex, simple in construction, light in weight, easy to use, and easy to transport from one location to another. U.S. Pat. No. 5,557,940 to Hendricks discloses a refrigerant heating unit. However, the Hendricks heating unit relies on a blower and heater to heat the refrigerant. The blower is heavy, making the unit difficult to transport to roof-tops to service roof-top air-conditioners.